Automatic control for firearms



Dec. 25, 1945. c. F. MULLEN AUTCMATIC CONTROL FOR FIREARMS Filed Nov.25, 1942 INVENTOR C/zaries F/Vuflen BY I ATTQRNLY Patented Dec. 25, 1945AUTOMATIC CONTROL FOR FIREARMS Charles F. Mullen, Long Branch, N. J.,asslgnor to Central Aircraft Corporation, Keyport, N. J., a corporationof Delaware Application November 25, 1942, Serial No. 466,912

2 Claims.

The present invention relates to means for controlling the operation offirearms, and more particularly to means for automatically controllingthe firing of adiustably mounted guns carried by aircraft.

One of the chief difiiculties to be contended with and overcome inadjustably mounting guns on aircraft is that of avoiding the accidentalhitting of parts of the aircraft on which the guns are mounted. Withguns that are fixedly mounted the problem is easily overcome as the gunmay be synchronized to fire through a moving part; that is, the gun ismechanically geared and fired only when the moving part is out of theline of fire. The problem is more difiicult in connection with flexiblymounted guns adapted to be aimed and fired by a gunner. While swingin agun in a path to follow a target, parts of the gunners own airplane maycome into the line of fire and be seriously damaged or shot away. Duringthe excitement of a battle the gunner should be free from having toworry about hitting parts of his own airplane. One way of overcomingthis difiiculty in connection with flexibly mounted guns is by camming"them. With this method, a form of cam surface is utilized to so guidethe gun or its mount at certain portions of its path, that it cannotcome into line with and shoot at a part of the aircraft which carriesthe gun. This method is objectionable for it frequently requiresrelatively complicated mechanism, is likely to suddenly and unexpectedlythrow the gunner off his aim, and it may increase the area of a blindspot due to the fact that where several comparatively small parts aregrouped relatively closely together, a single cam means must be utilizedto cause a gun to miss all of the parts as an entirety; it would beimpractical to control the gun by a number of cams so that the gun wouldseparately miss each of the closely positioned parts.

The present invention aims to overcome or minimize the above and otherdifficulties by providing a relatively simple means adapted to control agun so that it will not shoot while aimed at some object other than atarget, and which does not suddenly and unexpectedly throw a gunner oilhis target. The invention also contemplates the provision of automaticgun controlling grouped separate parts, instead of avoiding such partsas a single group as is done in the usual camming of guns.

An object of the present invention is to provide a new and improved guncontrolling means.

Another object of the invention is to provide means which may be used toavoid hitting closely a gun controlling means which is automatic inoperation.

Another object of the invention is to provide a gun controlling meansadapted to automatically stop the firing of the gun when it is aimed ata predetermined obstruction.

Another object of the present invention is to provide a gun controllingmeans adapted to automatically start the firing of a gun when its aim isdirected away from an obstruction.

Still another object of the invention is to provide a gun controllingmeans which is relatively simple in construction and operation and whichis easy to install.

A still further object of the invention is to provide a gun controllingmeans which does not throw a gunner out of a normal path of aim.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodiment about to be described, orwill be indicated in the appended claims, and various advantages notreferred to herein will occur to one skilled in the art upon employmentof the invention in practice.

A preferred embodiment of the invention has been chosen for purposes ofillustration and description and is shown in the accompanying drawing,forming a part of the specification, wherein,

Fig. 1 is a top plan view showing a gun mounting arrangement in anaircraft;

Fig. 2 is an elevational view, partly diagrammatic, showing a preferredembodiment of the invention;

Fig. 3 is a view of a screen adapted to be utilized in connection withcontrolling a firearm;

Fig. 4 is an elevational view, partly in section, showing one means forcontrolling the operation of a firearm; and

Fig, 5 illustrates a preferred wiring diagram for the controlling meansillustrated in Fig. 4.

Referring again to the drawing and more particularly to Fig. 1 thereof,there is shown an airplane I having tail booms 2 and 4 carrying adjacenttheir ends a horizontal controlling surface 5 and spaced, verticalcontrolling surfaces 1 and 8. A flexibly mounted gun I0 is shown locatedin a turret positioned adjacent the trailing edge of a wing andintermediate the tail booms of the airplane I. This location of the gunserves to illustrate the present invention, but it will be clear thatthe invention is equally applicable to guns mounted at any otherlocation on an aircraft. The chief function of the flexible gun I0 is toprotect the airplane I from attack by an enemy airplane approaching fromthe rear of the airof his own plane. Figs. 1 and 2 illustrate, by dot-'ted lines, the danger areas within'which a gun ner might hit his ownplane. Causing the gun or its mount to follow or'be guided by a camtrack at such danger areas presents the diflicul- Y ties referred tohereinabove.

In Fig. 2 the gun I and tail surfaces and I of an aircraft are showndiagrammatically to clearly bring out the present invention. Theflexible gun I 0 is intended to represent guns generally as theinvention is not limited to use with any particular type of gun. Alight-sensitive photocell II is preferably secured to the gun IE3adjacent 'the'breech thereoflso that moving the gun to aim itcorrespondingly moves the ph0t0- cell I I. The photocell I I .isconnected with suitable amplifier relays and th latter are operativelyconnected with a mechanism on the gun adapted to render the guninoperative when it is pointed at obstructions such as the tail surfaces5,! and 8. The'gun controlling mechanisms will be more fully describedhereinafter.

The gun controlling photocell II is set into operation by means of lightrays from alight source [4, which pass through suitable apertures orslits I9,.20, and 22 of a screen I3. The light source It maybe anelectric bulb of appropriate size .and brilliance. The light source I4is preferably contained within a box or receptacle l6 positionedadjacent the gun I 0 and photocell II. The box It may vbe mounted on apedestal ,I! which is stationarily secured to the airplane I, since itsrelation to obstructions to be avoided by gunfire isconstant. The screenI3, however, is preferably mounted so that it may be movedvertically'in' proportion to the height to which the gun Ill may beadjusted. The screen I3, through which pass the light rays given off bythe light source I4, is preferably an opaque material having'aperturesor slits I9, and 22 through which the light rays may pass. A reflectingback may be utilized in the box I 6 to direct a maximum amount of lightfrom bulb I4 through the screen apertures toward the photocell I I. Theapertures I9,,2li and 22 are a pattern or representation of theobstruction which it is desired to protect from gunfire. In the presentinstance the apertures of the screen I3 are shown in the shape of theairplane tailsurfaces which are to be protected from shots fired by thegun II). The slits should be wide enough to allow for movement of thecon trolling surfaces 5, 1 and '8 during flight.

The horizontal aperture or. slit-I9 in the screen of Fig. 3 representsthe tail booms 2 and 4 and the horizontal tail surface 5 of the airplaneand the vertical apertures or slits 20 and '22 represent the verticaltail surfaces I and 8 of the airplane. The screen I3 is so positioned,with respect to the photocell carried. by the gun, that when the gun I0is not aimed at anyof the tail surfaces the photocell II willbe oppositean opaque section 23 of the screen; the gun will then be firingnormally. 'When the gun I!) is aimed at any of he ail su a s t e h toll. w ll e n l n with one of the apertures or slits representing aportion of the tail surfaces. In this latter position, a current will beset up through various amplifyingrelays I8 connected with the photocelland these will in turn effect operation of a mechanism for stopping theoperation of the gun. It will be understood that any desired shapes andsizes of designs or patterns may be carried by the screen I3, dependingupon the shapes and sizes of the obstructions which it is desired toavoid hitting by gunfire. The amplifying relays, circuit connections, etcetera, are not illustrated in detail herein since they are generallyknown and do not form the subject matter of the present invention.Current for operating the light source [4, amplifying relays, and otherparts of the device may be supplied to the plug connections 9 j and I2from a battery or generator (not shown).

A gun may be rendered inoperative in numerous ways when pointed at anobstruction. For illustrative purposes, there will now be described oneway of controlling a gun by a type of auxiliary trigger, the latterbeing in turn operated by the photocell II. Figs. 4. and 5 illustratethe details of such a construction applied to a, fully automatic, gasoperated machine gun of the Lewis type. The Lewis type has beenselectedsince the features of its construction and operation are known and adescription of its automatic operation when embodying the presentinvention will serve to clearly illustrate one method of ,controllingthe operation of such guns. The first shot from such types of guns isfired by pulling :back on the trigger 28 to release a lever 29 from anotch 3! on the gas actuated operating rod 32 of the gun. Moving thelever 29 out of the'notch 3i of the operating rod 32 causes theoperating rod 32 to be impelled forwardly by a spring 34. The operatingrod 32 carries a firing pin 35 which is thrown against a cartridge 36 tofire it. The gas charge resulting from a first shot'effects return ofthe operating rod 32 and firing pin 35 to a rearward position in the gunand also re-. winds or compresses the actuating spring 3 l; theactuating spring 34 thereupon, again throws the operating rod and firingpin forwardly; against a new cartridge; whichhasautomatically beeninserted into the breech of the gun. ,The firing of the gun willcontinue until the ammunition gives out or until the gunner releases thetrigger 28. Releasing the trigger 28 -allowsthe spring 37 to move thelever 29 into engagement with the notch 3I of the operating rod -$2 andto thus hold back the firing pin 35. The present invention provides adetent member or augiliarytrigger 38 adapted to fit into the notch 2! ofthe operating rod 32 to stop the operation of the gun when the photocellis affected bylight rays which pass through the apertures orslits in thescreen I3. The detent or auxiliarytrigger 38 may be of the solenoid typeand may operate in dependently of the main trigger 28. q Movement of thegun It! into line with anylof the'tail surfaces 5, "i or 3 causescorresponding movement of the photocell II carrie'dthereby and alignmentthereof with a screen aperture 'or slit I9, 22') or 22 corresponding toone ofthetail surfaces. Light rays passingthrough one'fdf-the screenslits onto the photocellis'eifectiv'e tolfset into operation theamplifyin relays connected therewith. The amplified current flowsthrough the solenoid coil 40 and projectsthedetent or auxiliary trigger 38outwardly into, engagement with the notch 3! in the operating rod 32 of;the gun, This holds the operating rodand firing pin and thus stops theoperation of the gun. When the gun has swung out of line with a tailsurface or other obstruction the photocell H and the screen slits willbe out of alignment with each other and current through the solenoidwill immediately cease. A spring 4| may then move the detent orauxiliary trigger 38 out of the notch 3! so that the gun may immediatelycommence firing again, The stopping and starting of the gun arepractically instantaneous and the tail surfaces are effectivelyprotected from being hit by shots from the gun.

Vibrations of the gun due to firing do not affect the operation of thepresent gun controlling device. If the gun vibrates to a position suchthat the photocell H does not line up with a screen slit, the gun willthen also be out of line with a surface to be protected and may be firedwithout danger. However, any vibration of the gun which causes thephotocell H to line up with screen slit will automatically stop theoperation of the gun.

The above described means and method of controlling a flexibly mountedgun may be applied to guns of various types and sizes. Also, any othersuitable auxiliary trigger mechanism or the like may be utilized. It isbelieved that the operation of the present device will be clear from theforegoin detailed description and that further description of theoperation at this point would be superfluous.

While the preferred embodiment illustrates the present invention appliedto a single gun, the invention is applicable to a plurality of gunsoperated either jointly or independently. For example, four guns may bemounted at the corners of a square of suitable dimensions. The distancethe guns are spaced may be such that continuous firing is obtained andthat the obstruction will be in the line of fire of only part of theguns at any one time. Hence some of the guns will be firing at alltimes. By locating the guns at th corners of a square, for example, boththe lateral and vertical obstructions may be by-passed without stoppingthe firing of all of the guns. Other desired arrangements are alsointended to be included in the concept of the invention.

It will be seen that the present invention provides a new and improvedmeans and method for controlling the operation of flexibly mounted gunsso that a gunner will not accidentally shoot at obstructions which maycome into the line of.

fire. This device is particularly useful in connection with aircraft. Nocomplicated mechanism of cams, levers, et cetera, is used to control thegun. A gunner may swing a gun smoothly herein is to be interpretedas"illustrative"and not i along a path of fire without being suddenlystopped or thrown out of a natural path of fire by a cam whileattempting to follow the course of a moving target. The usual manuallycontrolled trigger of a firearm may be held continuously in firingposition by the gunner and the gun will automatically cease firing whenpointed at an obstruction and will immediately commence firing when theobstruction is out of the line of fire. The device is relatively simplein construction and easy to install.

As various changes may be made in the form, construction and arrangementof the parts herein without departing from the spirit and scope of theinvention and without sacrificing any of its advantages, it is to beunderstood that all matter in a limiting sense.

Having thus described my invention, I claim:

1. In a device of the class described for use in an airplane, thecombination of a firearm, means mounting said firearm for rotation abouta vertical axis and about a horizontal axis, a light sensitive photocellmounted on said firearm at a distance from said horizontal and verticalaxes, an enclosed light source spaced from said photocell and fixed withrespect to said mounting and comprising a screen having an opaqueportion and a light transmitting portion, said light transmittingportion having a contour constructed, positioned and arranged to directlight on said photocell when parts of the airplane are in the line ofgun fire and means operatively connected to the photocell to render thefiring mechanism inoperative while light is directed on said photocell.c

2. In a device of the class described for use in an airplane, thecombination of a firearm, means mounting said firearm for rotation abouta vertical axis and about a horizontal axis, a light sensitive photocellunit, an enclosed light source unit spaced from said photocell unit andcomprising a screen having an opaque portion and a light transmittingportion, one of said units being fixed with respect to said mounting andthe other of said units being mounted on said firearm at a distance fromsaid horizontal and vertical axes, said light transmitting portion ofthe screen having a contour constructed, positioned and arranged todirect light on said photocell unit when parts of the airplane are inthe line of fire, and means operatively connected to the photocell unitto render the firing mechanism inoperative while light is directed onsaid photocell unit.

CHARLES F. MULLEN.

